Change free axis rotation.

apps/opencs/model/prefs/state.cpp

@@ -188,6 +188,7 @@ void CSMPrefs::State::declare()
             "Shift-acceleration factor during drag operations", 4.0).
         setTooltip ("Acceleration factor during drag operations while holding down shift").
         setRange (0.001, 100.0);
+    declareDouble ("rotate-factor", "Free rotation factor", 0.007).setPrecision(4).setRange(0.0001, 0.1);
 
     declareCategory ("Tooltips");
     declareBool ("scene", "Show Tooltips in 3D scenes", true);

apps/opencs/view/render/instancemode.cpp

@@ -323,8 +323,40 @@ void CSVRender::InstanceMode::drag (const QPoint& pos, int diffX, int diffY, dou
         osg::Vec3f eye, centre, up;
         getWorldspaceWidget().getCamera()->getViewMatrix().getLookAt (eye, centre, up);
 
+        float angle;
+        osg::Vec3f axis;
+
+        if (mDragAxis == -1)
+        {
+            // Free rotate
+            float rotationFactor = CSMPrefs::get()["3D Scene Input"]["rotate-factor"].toDouble() * speedFactor;
+
+            osg::Quat cameraRotation = getWorldspaceWidget().getCamera()->getInverseViewMatrix().getRotate();
+
+            osg::Vec3f camForward = centre - eye;
+            osg::Vec3f screenDir = cameraRotation * osg::Vec3f(diffX, diffY, 0);
+            screenDir.normalize();
+
+            angle = std::sqrt(diffX*diffX + diffY*diffY) * rotationFactor;
+            axis = screenDir ^ camForward;
+        }
+        else
+        {
+            // Global axis rotation
             osg::Vec3f camBack = eye - centre;
 
+            for (int i = 0; i < 3; ++i)
+            {
+                if (i == mDragAxis)
+                    axis[i] = 1;
+                else
+                    axis[i] = 0;
+            }
+
+            // Flip axis if facing opposite side
+            if (camBack * axis < 0)
+                axis *= -1;
+
             // Convert coordinate system
             osg::Vec3f screenCenter = getScreenCoords(getSelectionCenter(selection));
 
@@ -343,26 +375,10 @@ void CSVRender::InstanceMode::drag (const QPoint& pos, int diffX, int diffY, dou
             newVec.normalize();
 
             // Find angle and axis of rotation
-        float angle = std::acos(oldVec * newVec) * speedFactor;
+            angle = std::acos(oldVec * newVec) * speedFactor;
             if (((oldVec ^ newVec) * camBack < 0) ^ (camBack.z() < 0))
                 angle *= -1;
-
-        osg::Vec3f axis;
-        if (mDragAxis != -1)
-        {
-            for (int i = 0; i < 3; ++i)
-            {
-                if (i == mDragAxis)
-                    axis[i] = 1;
-                else
-                    axis[i] = 0;
-            }
-
-            if (camBack * axis < 0)
-                axis *= -1;
         }
-        else
-            axis = camBack;
 
         rotation = osg::Quat(angle, axis);
     }